Existing and proposed large multi-satellite constellation systems are expensive to build and place into orbit. Because of the expense, it is desirable to fully capture payment for communication services provided to authorized users and minimize the amount of services provided to unauthorized users. Both authorized and unauthorized users can utilize the capacity of these constellations. The satellite communication system must restrict the amount of services being provided to unauthorized users so that constellation capacity is fully utilized by authorized users.
A "satellite" is defined herein to mean a man-made object or vehicle intended to orbit Earth and includes both geostationary and orbiting satellites and/or combinations thereof. A "constellation" is defined herein to mean an ensemble of satellites arranged in orbits for providing specified coverage of a portion or all portions of the celestial body. A constellation typically includes multiple rings (or planes) of satellites and can have equal numbers of satellites in each plane, although this is not essential.
Communication units in a mobile communication system occasionally perform call setup procedures which require system resources from the system to which they currently subscribe. Call setup procedures are required to enable the system to contact the called communication unit when a call attempt is destined for that communication unit, and system resources must be allocated for the call. Call setup information forms the basis for many billing purposes.
Each call set-up procedure involves an exchange of messages between the initiating communication unit and the system and between the system and a termination communication unit. These call set-up messages generate communication traffic which is non-revenue bearing in nature. These call set-up processes can be compromised by fraudulent users to gain access to communication services which are also non-revenue bearing. The non-revenue bearing traffic volume is compounded when any communication unit or groups of communication units engage in fraudulent use of system resources and services.
In prior art systems, mission traffic paths were completed before the signaling process was completed. This allowed fraudulent users to use system resources until the signaling process ended. This did not occur until the last timer expired. Prior art call set up procedures required each communication unit to react as it was designed to react within the system. This requirement can be costly to the system and can result in a large amount of non-revenue bearing traffic.
What are needed are a method and apparatus for detecting the fraudulent use of system resources during the call set-up process. Further, a method and apparatus are needed to prevent the fraudulent use of system resources during the call set-up process.